Torsion suspension



' Oct. 1, 1940. E. H. l =lRON 2,216,455

TORSION susPENsIon Filed Jan. 27, 1938 2 Sheets-Sheet l v BY I E 5 ATTORNEY Get. 1, 1940. E, PlRoN 2,216,455

TORSION SUSPENSION 7 Filed Jan. 27, 1938 2 Sheets sheet 2 INVENTOR. EM/L H P/KOM BY a,

ATTORNEY.

UNITED STATES FFHZE 2,216,455 TORSION SUSPENSION Emil H. Piron, New York, N. Y., assignor to Transit Research Corporation, New York, N. Y., a corporation of New York Application January 27, 1938, Serial No. 187,181.

4 Claims. (01. 267-21) This invention relates to vehicle springing sysand the system herein revealed is of this latter tems adapted for heavy service and has for its type. Torsion springs are advantageous because object to proi de a system which will have 1111-- it is possible to obtain greater resistance to disproved load resisting characteristics, these imtortions in directions other than the direction of 5 proved characteristics being substantially uniprincipal loading and because of the facility with form over the entire range of loading from minlwhich they may be employed in series. The ad- 5 mum to maximum thereby to provide improved vantages of series springing will now be exriding quality, ,reduced wear and tear on the Dlained. v

vehicle itself and the load being transmitted The loading must be transmitted from or to and prolonged life of the vehicle tires. a relatively small shaft through rubber'in torsion 10 s mm Such as freight hauling tr k to or from a cylindrical casing. Practical rebuses, rail trucks and the like are subjected to quirements of rubber manufacture limit the P extreme variations 1n load. In the case of some sible thickness of rubber to the extent that the trucks, for instance, the weight of the empty body outside diameter thereof should not generally exmay be only about three thousand pounds and ceed about twice the inside diameter and the 15 yet it may be subjected to a loading running limit of torsional movement is limited to twenty from zero to twenty tons. The springs are, or twenty-fiv degrees. therefore, necessarily designed to support the In Order to Obtain the riding q y herein maximum load and hence are, in many cases, contemplated it is necessary that the Springs substantially wlthout resilience under the weight v a nstan issi factor, nd pendent of the empty body. Such a truck may make a. of theload, this factor being defined as that delivery to some distant point and then return proportion o an impulse a t e-Wheels trans empty, at speed, Th ar on ti e and body mitted through the springs to the vehicle body. during "the return trip is many time g t r It is a function of the square of the natural frethan during delivery which gives an indication of q y of Osc llation of the sp n y 9f 25 the great importance to the life of the vehicle the ratio of good riding quality at all times aside from the k breakage and deterioration of a pay load supw.

ported by poor springs and aside from rapid I deterioration of highways due to thissame cause. Where w 18 the load and k the instantaneous It is," therefore, a principal object of this inven- 22322? g f Sprmg ratio and may 30 tion to provide a spring suspension which will k of increase of 10 a d give improved riding quality under maximum loading and which will have equally good riding lmfrease of deflection quality under minimum mad conditions Analysis of this ratio shows that, if .the ratio 35 Elastic material such as rubber, or its equiv k is constant for various values of the ratio alents, have certain inherent advantages for yejg hicle springing, among which are lack of mew v Chemical friCtiOn, P p response to Small move: the transmission factor decreases as 10, increases 40 ments, freedom, from the necessity of lubrication with't'he result that a spring/having a correct de- 40 of e a y movable parts, the i y o absorb flection value at minimum load becomes too soft a substantial amount of energy and adaptability, under heavy loads. to various designs whereby length dnay be sub- In the case of a rubber torsion spring the stituted for width or viceversa and the readiness torque reaction is proportional to the angle of 5 with which lever arms may be applied thereto. torsion. If the spring is given a lever arm and Another object of the invention is to teach the a vertical load imposed thereon, the' vertical application of elastic springs to vehicles in such reaction is prop rtional to the torque reaction manner as to make use of these several addivided by the horizontal projection of'its lever vant es While adapting the design hereof to my arm. Figure l of the drawings is illustrative of invention. this, the center 0 indicating the center or axis of 50 Rubber in shear has many advantages in a shaft embedded in and rotatable against the springing systems as has also rubber in com resistance of a rubber cylinder D, the cylinder pression. Where spring deflections of conslderbeing surrounded by a housing Ev fixed on a veable magnitude are desirable, however, it is often hicle body. The vertical load w resisted by the times more desirable to employ rubber in torsion torque reaction is proportional to the torque re- 55 action divided by the horizontal projection C of the spring arm A0 which supports the load w.

B0 is the position of the spring arm when the spring is in its released position; If the angle B00 is indicated as a, the angle of distortion AOB as b and the torque reaction is T, the load supported by such a torque is T R cos (a.+b) The deflection d=[sin (a+b) sin a] where R=AO, the-length of the spring arm.

Now, it is possible to find a value for a which gives values for k which vary almost in direct proportion with w, or some desirable function of w, over a wide range of deflection provided the value of. b between minimum and maximum load varies through an angle of 40 to 50 but this cannot be done where the variation of b is limited to 20 to 25. It follows that a successful design for a torsion spring for widely varying loads depends on the possibility of using it through an angle of 40 to 50 or even more as it can then be proportioned so as to produce a springing system with an almost constant natural frequency through the range of various loads encountered in industrial practice. The foregoing leads to the conclusion that a torsion spring expected to give good riding quality under the severe requirements herein contemplated must be composed at least of two elements in series as far as the deflections are concerned, so as to have a torsion angle of approximately 40 or more available for distortion. It is, therefore, an object of the invention to provide a springing system comprising parallel sets of elastic torsion springs arranged in series, the springs of each set being so connected to each other and to the vehicle as to give a substantially constant transmission factor or, even, a transmission factor which increases with the load rather than decreases, as is the casein ordinary springs.

Other objects and advantages will hereinafter become more apparent as reference is had to the accompanying drawings wherein:

Fig. 1 is a diagramof the operation of a torsion spring for purposes of illustration,

Figs. 2, 3 and 4 are elevations of different types of series torsional springs,

Figs. 5, 6 and '7 are transverse sections taken along the lines 5-5, 6 6," 1-1 respectively of Figs. 2, 3 and 4.

Fig. 8 is a plan view of separate torsion springs arranged in series,

Fig. 9 is a side elevation of the springs of Fig. 8,

Fig. 10 shows a side elevation of, a spring of the general type of that of Fig. 4 applied to a vehicle frame,

Fig. 11 is a bottom plan view of the spring of Fig. 10,

Fig. 12 is a perspective view of the rear of a vehicle frame completely equipped with my improved suspension, and

Fig. 13 is a bottom plan view of the suspension of one side of the frame of Fig. 10.

Fig. 1 has been described in the preamble wherein the necessity for springing in series was explained. Series springing may be obtained in several different ways, four of which are herewith.

illustrated in order to indicate the possible range of design according to the room available and" other exigencies.

In Figs. 2 and 5 a plurality of metallic rings I are arranged concentrically about a shaft 2 and interposed therebetween are cylinders 3 of elastic material surface bonded to the adjacent metallic members at each surface. If torque loading is applied to the shaft I, torque is transmitted progressively through the elastic elements.

In Figs. 3 and 6 coaxial shafts 4 and 5 extend through coaxial elastic cylinders 6 and 1 surface bonded to a common cylindrical casing 8. A torque applied to the shaft 4 is transmitted through the element 6 then to the casing 8 then to the element I and then to the shaft 5.

In Figs. 4 and 7 a single shaft 9 extends axially through two spaced cylindrical elastic elements l0 and II positioned in and surface bonded respectively to housings l2 and I3. A torque applied to the casing I2 is transmitted through the element II) to the shaft 9 then through the element H to the casing I3.

In Figs. 8 and 9 separate springs M and [5 are connected for series operation by a link l6 fixedly secured to the outer casings thereof. These springs may each be composed of a cylindrical housing, a central shaft H or l8 and cylindrical sleeves of rubber i9 surface bonded to a shaft and housing at its inner and outer surfaces respectively, or they may each be composed of any of the springs described in connection with Figs. 2 to 7. One shaft i8 is non-rotatably secured to one or more levers or torque arms 22. This form of spring grouping has certain advantages such as good stability against horizontal forces, absence of mechanical friction at any joint and hence absence of operating troubles generally caused by lubrication, clearance adjustments and the like. The fixed relation of the arms 22 and the shaft I! should be particularly noted. If vertical loading without the torque arm is imposed on the shaft I! there will be a simple cushioning action by the element l9 thereabout and, in response to movement of the arm IS, the other element ill will thereafter be subjected to torsion.

Figs. 10 and 11 illustrate an application of torsion springs to a vehicle in accordance with my invention. Any of the springs illustrated in Figs. 2 to 7 inclusive may be used but for purposes of instruction a modified form of the spring of Figs. 4 and 7 is chosen. One spring is composed of a casing 23 fixedly secured to a bracket 24 attached to a vehicle frame member 25, the casing containing a cylinder 26 of rubber to the interior surface of which a shaft 21 is surface-bonded. This shaft projects outwardlyof the rubber at both ends for extension through additional rubber cylinders 28 and 29, to which it is surface bonded- The exterior surfaces of the sleeves 28 and 29 are surfacebonded. The exterior surfaces of the sleeves 28 and 29 are surface-bonded to housings 30 each of which is fixedly secured to torque arms 3i in which an axle 32 is journalled. The springs 28, 29 and 30 may be considered as half springs in which case the similarity to the spring of Figs. 4

- and 7 will be obvious.

Under empty body loadters of the shafts 21 and 32, the weight supported s identical in construction and consequently only one will be referred to.

Two brackets 34 and 35 are secured to the frame 33 in longitudinally spaced relation. Each bracket is integral with or fixedly secured to a spring housing 36 to the interior of which an elastic sleeve 31 is surface-bonded. A shaft 38 extends through the sleeve 31 and outwardly of each end thereof for extension through the rubber sleeves 39. Enclosing each sleeve 39 is a housing 40 having a torque arm 4| each of which is integrally or fixedly secured to a housing 42 which encloses a sleeve of rubber 43. A

second shaft 44 extends axially through the sleeves 43 and through a further sleeve 45 placed between the sleeves 43, the sleeve 45 being housed by a casing 46 which is fixedly or integrally secured to a torque arm 41. The arm 41 is common to the two series of longitudinally spaced springs and constitutes a beam for attachment of the vehicle axle 48 thereto, the axle being journalled therein at 49. From the foregoing it will be seen that the two series of longitudinally spaced springs are identical except for the brackets 34 and 35, the bracket being preferably divided at 50 in order to centralize the beam with respect thereto.

It will be understood, in connection with the foregoing description, that the sleeves 31, 39, 43 and are in contact with and preferably surface bonded to their respective housings and shafts.

The illustration shows the approximate spring positions under empty body or no pay-load conditions. The torque arms 4|, therefore, have an angle with the horizontal, and if T is the torque reaction of each element (assuming these elements to be identical), the torque reaction of a spring with torsion elements at each end of the spring arm is 2T and the equation for the load becomes 2T R .cos (a-l-b) This invention may be developed within the scope of the following claims without departing from the essential features of the said invention and it is desired that this specification and draw- 53 ings be read as being merely illustrative and not in a limiting sense, except as necessitated by the prior art.

What I claim is:

1. A vehicle suspension comprising a frame and a pair of rigid elongate beams residing on opposite sides of the vehicle with each extending fore and aft thereof, a bearing for an axle carried by each of said beams, torsion spring means connected to said frame at each end of each of said beams, and a torque arm connected to each of said spring means and pivotally connected to the adjacent beam, said torque arms all extending in like directions and normally residing at like angles with respect to both the horizontal and the vertical.

2. A vehicle suspension comprising a frame and a pair of rigid elongate beams residing on opposite sides of the vehicle with each extending fore and aft thereof, a bearing for an axle carried by each of said beams, torsion spring means connected to said frame at each end of each of said beams, and a torque arm connected to each of said torsion springs and connected through an elastic sleeve to the adjacent beam, the torque arms all extending in like directions and normally residing at like angles with respect to both, the horizontal and the vertical.

3. A vehicle suspension comprising a frame and a pair of rigid elongate beams residing on opposite sides of the vehicle with each extending fore and aft thereof, a bearing for an axle carried by each of said beams, torsion springmeans connected to said frame at each end of each of said beams, a torque arm connected to each of said spring means and pivotally connected through an elastic sleeve to the adjacent beam, all of said torque arms extending in like directions and at like angles, said sleeve in each case also comprising a torsion spring.

4. A vehicle suspension comprising a frame, a

pair of elongate beams, one at each side of the vehicle and extending fore and aft thereof, an axle bearing carried by each of said beams, a plurality of elastic springs at each end of said beams arranged in series to resist vertical loading imposed by said beams in torsion, torque arms connecting said beams and said springs, said torque arms extending in like directions and at like angles, and a plurality of elastic springs arranged in series to resist vertical loading in torsion constituting the connection of said torque arms to the ends of said beams.

EM'JL H. PIRON. 

